This application claims priority of Japanese Application No. 2000-316977 filed Oct. 17, 2000, the complete disclosure of which is hereby incorporated by reference.
The present invention relates to an ion selective monoelectrode complex and an ionic activity-measuring apparatus which is favorably employable for analysis of ionic components in liquid samples such as a whole blood sample, a serum sample, and a urine sample.
An ionic activity-measuring apparatus utilizing an ion selective electrode is widely employed for analyzing ionic components in a liquid sample such as a whole blood sample or a serum sample.
U.S. Pat. No. 4,571,293 (which corresponds to EP 0 160 997 B1) discloses an ionic activity-measuring apparatus using an ion selective electrode which is illustrated in FIG. 1 of the drawings attached to this specification.
In FIG. 1, the ionic activity-measuring apparatus comprises a non-electroconductive support 11, a pair of electrodes each of which comprises a silver metal layer 12a, 12b and a silver halide layer 13a, 13b, a common electrolytic material layer 14, a common ion selective membrane 15, and a common non-electroconductive cover sheet 16 having a pair of openings 17a, 17b for receiving and keeping a sample solution and a reference solution, respectively, each opening being placed above each electrode unit, and having thereon an a bridge member 18 for electrically bridging the sample solution received in one opening 17a and the reference solution received in another opening 17b. Each of the silver metal layer 12a, 12b has an exposed surface 10a, 10b, respectively. By placing probes of a potentiometer 19 on these exposed silver metal surface 10a, 10b, the produced electric potential difference can be measured.
FIG. 2 illustrates an industrially employed process for preparing the ionic activity-measuring apparatus of FIG. 1.
In industry, the ionic activity-measuring apparatus of FIG. 1 is generally manufactured in a mass scale, by the steps of:
(1) preparing a longitudinal sheet composed of a non-electroconductive sheet 11 and a silver metal layer 12 deposited or laminated on the non-electroconductive sheet 11;
(2) making a linear scratch 21 on the silver metal layer 12 under the condition that the scratch is extended in the longitudinal direction and reach the non-electroconductive sheet 11, to divide the silver metal layer 12 into two silver metal portions 12a, 12b, and covering each silver metal portion 12a, 12b on its side areas with a polymer material layer 20a, 20b, leaving uncovered area in the form of a stripe (or belt) on the silver metal portion 12a, 12b; 
(3) halogenating the silver metal portion 12a, 12b in the uncovered areas to form silver halide layers 13a, 13b, respectively, on the surface of the silver metal portion in the uncovered area;
(4) forming an electrolytic material layer 14 on the scratch and the silver halide portions;
(5) peeling the polymer material layer 20a, 20b off from the silver metal layer to produce an exposed silver metal area 10a, 10b, and placing an ion selective membrane 15 on an electrolytic material layer 14; and
(6) finally placing a non-electroconductive member 16 having two openings 17a, 17b on the ion selective membrane 15 and then placing a bridge 18 on the member 16 to connect the openings 12a, 17b. 
The above-described industrial method is advantageous for manufacturing a great number of ion selective electrodes in a mass scale.
The ion selective electrode can measure an ionic activity of H+, Li+, Na+, K+, Mg2+, Ca2+, Clxe2x88x92, HCO3xe2x88x92, or CO32xe2x88x92, by employing an appropriate ion selective membrane.
U.S. Pat. No. 4,789,435 describes an ion selective electrode assembly comprising plural ion selective electrodes for analyzing plural ionic components such as Na+, K+, and Clxe2x88x92, simultaneously. In the assembly, one of plural ion selective electrodes has an ion selective membrane differing from that of other ion selective electrode in chemical composition.
It is an object of the present invention to provide an ion selective electrode having a satisfactory analytical performance at a relatively low production cost.
The object of the invention also resides in providing a method of manufacturing ion selective electrodes having satisfactory analytical performance in a mass scale at a relatively low production cost.
The present invention resides in an ion selective monoelectrode complex (hereinafter referred to as xe2x80x9cType Axe2x80x9d complex), on a common non-electroconductive support sheet, plural ion selective monoelectrodes each of which is composed of an electrode composite comprising, in order, a silver metal layer, a silver halide layer, an electrolytic material layer, and an ion selective membrane, and an electroconductive terminal which is electrically connected to the silver metal layer and which has an exposed surface, under the condition that the ion selective monoelectrodes are aligned, without electric contact with each other, along an imaginary line bridging the electrode composite and the electroconductive terminal
The above-mentioned ion selective electrode of Type A is preferably manufactured in a mass scale by a process comprising the steps of:
making two or more linear scratches on a longitudinal non-electroconductive sheet having thereon a silver metal layer under the condition that the scratches are extended in the longitudinal direction and reach the non-electroconductive sheet;
covering the silver metal layer with a polymer material layer in the form of a stripe on one side of each linear scratch, leaving uncovered area in the form of a stripe;
halogenating the silver metal layer in the uncovered area to form a silver halide layer on the surface of the silver metal layer in the uncovered area;
forming an electrolytic material layer on the polymer material layer and the silver halide layer;
peeling the polymer material layer off from the silver metal layer to remove the polymer material layer and the electrolytic material layer placed on the polymer material layer simultaneously;
placing an ion selective membrane on an electrolytic material layer formed on the silver halide layer; and
cutting thus processed longitudinal sheet in the direction traversing the longitudinal sheet to give a plurality of the ion selective monoelectrode complexes.
The ion selective electrode of Type A is also preferably manufactured in a mass scale by a process comprising the steps of:
covering a longitudinal non-electroconductive sheet having thereon a silver metal layer with two or more polymer material layers in the form of a stripe in the longitudinal direction, leaving uncovered area in the form of a stripe;
making one or more linear scratches on the silver metal layer in the vicinity of the polymer material layers under the condition that the scratches are extended in the longitudinal direction and reach the non-electroconductive sheet;
halogenating the silver metal layer in the uncovered area to form a silver halide layer on the surface of the silver metal layer in the uncovered area;
forming an electrolytic material layer on the polymer material layer and the silver halide layer;
peeling the polymer material layer off from the silver metal layer to remove the polymer material layer and the electrolytic material layer placed on the polymer material layer, simultaneously;
placing an ion selective membrane on an electrolytic material layer formed on the silver halide layer; and
cutting thus processed longitudinal sheet in the direction traversing the longitudinal sheet to give a plurality of the ion selective monoelectrode complexes.
The present invention also resides in an ionic activity measuring apparatus (of Type A) comprising a pair of the ion selective monoelectrode complex, which are arranged in parallel without electric contact with each other, a non-electroconductive covering element having openings which is placed on the ion selective membranes of the complexes to receive and keep an applied liquid sample to bring it into contact with an ion selective membrane of each ion selective monoelectrode, and bridge elements placed on the covering element to connect one opening placed on an ion selective membrane of one ion selective monoelectrode complex with other opening placed on an ion selective membrane of another ion selective monoelectrode complex.
The invention further resides in an ion selective monoelectrode complex (hereinafter referred to as xe2x80x9cType Bxe2x80x9d complex), having, on a common non-electroconductive support sheet, plural ion selective monoelectrodes each of which is composed of an electrode composite comprising, in order, a silver metal layer, a silver halide layer, an electrolytic material layer, and an ion selective membrane, all silver metal layers being electrically connected with each other, and an electroconductive terminal which is electrically connected to one of the silver metal layers and which has an exposed surface, under the condition that the ion selective monoelectrodes are aligned along an imaginary line bridging the electrode composite and the electroconductive terminal.
The above-mentioned ion selective electrode (of Type B) of the invention is preferably manufactured in a mass scale by a process comprising the steps of:
covering a silver metal layer placed on a longitudinal non-electroconductive sheet with a polymer material layer in the form of a stripe on a side of the sheet, leaving uncovered area in the form of a stripe;
halogenating the silver metal layer in the uncovered area to form a silver halide layer on the surface of the silver metal layer in the uncovered area;
forming an electrolytic material layer on the polymer material layer and the silver halide layer;
peeling the polymer material layer off from the silver metal layer to remove the polymer material layer and the electrolytic material layer placed on the polymer material layer, simultaneously;
placing an ion selective membrane on an electrolytic material layer formed on the silver halide layer; and
cutting thus processed longitudinal sheet in the direction traversing the longitudinal sheet to give a plurality of the ion selective monoelectrode complexes.
The invention furthermore resides in an ionic activity measuring apparatus (of Type B) comprising a pair of the ion selective monoelectrode complex, which are arranged in parallel without electric contact with each other, a non-electroconductive covering element having openings which is placed on the ion selective membranes of the complexes to receive and keep an applied liquid sample to bring it into contact with an ion selective membrane of each ion selective monoelectrode, and bridge elements placed on the covering element to connect one opening placed on an ion selective membrane of one ion selective monoelectrode complex with other opening placed on an ion selective membrane of another ion selective monoelectrode complex.